Potassium is an essential nutrient used by the body to help maintain the muscles and organs, including the heart. Under normal circumstances, the body regulates this mineral in the bloodstream, using the kidneys to filter out any excess, but various factors can result in high potassium levels. External symptoms of this condition can be mild, and include sudden weakness, fatigue, or nausea. This makes it all the more dangerous, because high potassium levels can cause a fatal heart attack without warning. Doctors will often check the levels of patients at risk, such as those who have kidney disease or are taking potassium supplements.
High potassium levels, also called hyperkalemia, result in cell failure on a systemic level. This can cause symptoms such as hyperventilation, nausea, and unexplained changes in pulse rate. These symptoms are very non-specific, making the condition very difficult for a medical professional to diagnose without blood or kidney testing. Often, there are no observable symptoms at all.
A person with undiagnosed hyperkalemia might simply collapse from heart failure without warning. If immediate measures are not taken to reduce the amount of potassium in the body, the condition can be fatal. Fortunately, most people at risk for developing high levels of this mineral are already under the care of a medical professional for another condition, and should have their blood potassium levels tested regularly.
Potassium and Health
Most foods, particularly fruits such as banana and avocado, naturally contain potassium. Small quantities are distributed throughout the cells of the body, including the blood cells. Removing excess potassium from the blood is one of the principal functions of the kidneys; in a healthy individual, it will be excreted as waste. Some medical conditions and treatments can hamper this process, causing the body to retain more of the mineral than it needs.
Definition and Causes of High Levels
In a healthy adult, the level of potassium should be between 3.5 and 5.0 mEq/L, which is a measurement of the concentration in a given amount of blood. Levels higher than 5.1 are considered dangerous, and levels higher than 6.0 constitute an emergency that requires immediate medical treatment. Medical professionals rarely check a patient's potassium levels, however, unless they are being treated for a condition like kidney disease.
Because of the kidneys' role in controlling the amount of different chemicals in the body, kidney disease or malfunction is one of the most common causes of high potassium levels. Some medications can also interfere with the body's ability to process and excrete this mineral. Disease or sudden trauma can occasionally cause blood cells to release potassium into the bloodstream, resulting in hyperkalemia. Unfortunately, this can also cause a blood test to be inaccurate if the cells rupture when the blood is being drawn.
In some cases, a person's diet can also cause this condition. Salt substitutes, many of which are used by heart patients, often include potassium chloride, which looks like table salt and has a similar flavor. Even in these cases, however, fatal levels will rarely accumulate unless the patient also has undiagnosed kidney or digestive problems.
Patients at risk for hyperkalemia should avoid salt substitutes, as well as foods with high levels of potassium. It is possible to "leach," or remove, the mineral from vegetables by soaking them in water for extended periods of time. Certain medications, like sodium bicarbonate and diuretics, may also help lower high potassium levels in the blood.
Emergency care for high potassium levels can include intravenous glucose or insulin, which will reduce the amount of potassium in the bloodstream. Calcium can help minimize the mineral's effect on the heart. Hemodialysis, in which the blood is filtered by a machine outside of the body, is one of the most reliable treatments.
Legal jurisdictions that practice lethal injection as a form of capital punishment make intentional use of hyperkalemia. The chemicals used in the execution process include potassium chloride, which is considered a humane way to shut down the heart; this compound is also used in some euthanasia devices. Less controversially, the chemical is sometimes used in cardiac surgery to stop the heart when a procedure cannot be performed when it's beating.